Step 1: Prepare for Baking: First things first, preheat your oven to a cozy 350°F (175°C). Then, grab a 12"x17" half-sheet pan. Line it with parchment paper, leaving a little overhang on the sides for easy lifting later, and give the parchment and the exposed pan sides a light spray with cooking spray. This little trick makes cleanup a breeze!
Step 2: Mix the Batter: In a large mixing bowl, you're going to start by creaming together your softened butter and white sugar until it's light and fluffy. Now, crack in those eggs one at a time, beating well after each addition to ensure they're fully incorporated. In a separate, medium-sized bowl, sift together all your dry ingredients: the flour, salt, cinnamon, baking soda, and baking powder. Sifting really helps make your bars light and airy! Gradually add these dry ingredients to your wet mixture, alternating with the pumpkin puree, mixing until everything is just combined and beautifully smooth. Be careful not to overmix here; we want tender bars, not tough ones!
Step 3: Bake the Bars: Pour that gorgeous, spiced pumpkin batter into your prepared sheet pan. Use an offset spatula or the back of a spoon to smooth the surface evenly. Pop it into your preheated oven and bake for 20-25 minutes. You'll know they're ready when a toothpick inserted into the center comes out clean. Once baked, let those golden bars cool completely on a wire rack. Patience is key here – frosting warm bars will lead to a melty mess!
Step 4: Make the Frosting: While your bars are cooling, it’s time for the crowning glory – the cream cheese frosting! In a separate bowl, beat the softened cream cheese, softened butter, and pure vanilla extract until the mixture is wonderfully creamy and smooth. Now, gradually add the confectioners’ sugar, beating until you reach your desired frosting consistency. I usually add it in about 1-cup increments. If your frosting feels a little too stiff, no worries! Just add milk, 1 tablespoon at a time, until it’s perfectly spreadable. I find a rich, thick frosting is best, but you do you!
Step 5: Frost and Serve: Once your pumpkin bars are completely cool (and I mean completely cool!), spread that luscious cream cheese frosting evenly over the top. Then, using a sharp knife, slice the bars into squares or rectangles. Serve them up and watch them disappear!